A carriage-type heat treatment furnace is a batch-operated industrial heating device. Its core operating principle lies in generating heat through electric energy or fuel combustion, thereby heating workpieces to specific temperatures and maintaining those temperatures for a set period. This process enables various heat treatment operations such as quenching, annealing, and tempering, which in turn alter the internal microstructure and properties of metallic materials.

　　A carriage-type heat treatment furnace is a batch-operated industrial heating device. Its core operating principle lies in generating heat through electric energy or fuel combustion, thereby heating workpieces to specific temperatures and maintaining those temperatures for a set period. This process enables various heat treatment operations such as quenching, annealing, and tempering, which in turn alter the internal microstructure and properties of metallic materials.

　　Heating Method and Heat Source

　　The heat sources for walking-beam furnaces are mainly divided into two types: electric heating and fuel combustion. Electric-heating furnaces use high-temperature resistance alloy wires or corrugated resistance strips as heating elements; when energized, they convert electrical energy into thermal energy. Fuel-combustion furnaces, on the other hand, utilize fuels such as gas, which are burned through burners to generate heat. Some designs incorporate a preheated-air circulation system to enhance thermal efficiency.

　　The heat sources are typically arranged on the side walls, rear wall, furnace door, and surface of the trolley within the furnace chamber, ensuring that heat is evenly distributed to the workpieces from multiple directions.

　　Temperature Control and Regulation

　　Temperature control relies on a multi-zone independent PID system. The furnace is divided into multiple temperature zones (such as 6 zones or 12 zones), each equipped with a thermocouple for real-time temperature monitoring and data feedback to an intelligent digital display instrument.

　　The control system dynamically adjusts the heating power via a zero-crossing trigger circuit for thyristors: In the initial stage, it rapidly heats up at full power; as the temperature approaches the target value, the power is automatically reduced to enter a constant-temperature mode. By employing an intermittent power supply method, the temperature fluctuation is kept within a range of ±1℃ to ±5℃.

　　The preset heat treatment process curve (such as the staged heating rate) is automatically executed by the program.

　　Workpiece loading and unloading mechanism

　　The trolley, serving as a movable furnace bottom, is driven in and out via a sprocket-chain transmission mechanism or a cylinder-driven actuator.

　　The workpieces are placed directly onto the heat-resistant steel hearth plate on the trolley (typically designed with segmented grooves). The trolley is connected to the furnace body via a soft fiber-cotton seal, a sand seal, or a blade-type sealing structure, which helps minimize heat loss and accommodate thermal expansion at high temperatures.

　　The furnace door is equipped with a spring-loaded closure or an electric actuator for lifting and lowering, ensuring a tight seal.

　　Safety Protection and Energy-Saving Design

　　The safety system includes interlocking control: when the furnace door is opened, the heating power supply is automatically cut off; and when the trolley is in motion, the heating circuit is disconnected, thereby preventing accidental operation-related incidents.

　　The fuel furnace is additionally equipped with gas underpressure protection, flame-out interlock, and an explosion-proof device.